// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GPU_COMMAND_BUFFER_SERVICE_SHADER_TRANSLATOR_CACHE_H_
#define GPU_COMMAND_BUFFER_SERVICE_SHADER_TRANSLATOR_CACHE_H_

#include <string.h>

#include <map>

#include "base/memory/ref_counted.h"
#include "gpu/command_buffer/service/shader_translator.h"
#include "third_party/angle/include/GLSLANG/ShaderLang.h"

namespace gpu {
namespace gles2 {

    // This class is not thread safe and can only be created and destroyed
    // on a single thread. But it is safe to use two independent instances on two
    // threads without synchronization.
    //
    // TODO(backer): Investigate using glReleaseShaderCompiler as an alternative to
    // to this cache.
    class GPU_EXPORT ShaderTranslatorCache
        : public base::RefCounted<ShaderTranslatorCache>,
          public NON_EXPORTED_BASE(ShaderTranslator::DestructionObserver) {
    public:
        ShaderTranslatorCache();

        // ShaderTranslator::DestructionObserver implementation
        void OnDestruct(ShaderTranslator* translator) override;

        scoped_refptr<ShaderTranslator> GetTranslator(
            sh::GLenum shader_type,
            ShShaderSpec shader_spec,
            const ShBuiltInResources* resources,
            ShShaderOutput shader_output_language,
            ShCompileOptions driver_bug_workarounds);

    private:
        friend class base::RefCounted<ShaderTranslatorCache>;
        friend class ShaderTranslatorCacheTest_InitParamComparable_Test;
        ~ShaderTranslatorCache() override;

        // Parameters passed into ShaderTranslator::Init
        struct ShaderTranslatorInitParams {
            sh::GLenum shader_type;
            ShShaderSpec shader_spec;
            ShBuiltInResources resources;
            ShShaderOutput shader_output_language;
            ShCompileOptions driver_bug_workarounds;

            ShaderTranslatorInitParams(sh::GLenum shader_type,
                ShShaderSpec shader_spec,
                const ShBuiltInResources& resources,
                ShShaderOutput shader_output_language,
                ShCompileOptions driver_bug_workarounds)
            {
                memset(this, 0, sizeof(*this));
                this->shader_type = shader_type;
                this->shader_spec = shader_spec;
                this->resources = resources;
                this->shader_output_language = shader_output_language;
                this->driver_bug_workarounds = driver_bug_workarounds;
            }

            ShaderTranslatorInitParams(const ShaderTranslatorInitParams& params)
            {
                memcpy(this, &params, sizeof(*this));
            }

            bool operator==(const ShaderTranslatorInitParams& params) const
            {
                return memcmp(&params, this, sizeof(*this)) == 0;
            }

            bool operator<(const ShaderTranslatorInitParams& params) const
            {
                return memcmp(&params, this, sizeof(*this)) < 0;
            }

        private:
            ShaderTranslatorInitParams();
            ShaderTranslatorInitParams& operator=(const ShaderTranslatorInitParams&);
        };

        typedef std::map<ShaderTranslatorInitParams, ShaderTranslator*> Cache;
        Cache cache_;

        DISALLOW_COPY_AND_ASSIGN(ShaderTranslatorCache);
    };

} // namespace gles2
} // namespace gpu

#endif // GPU_COMMAND_BUFFER_SERVICE_SHADER_TRANSLATOR_CACHE_H_
